COMPARISON OF GENETIC-VARIABILITY OF NORTH-ATLANTIC AND SOUTH-ATLANTIC RIGHT-WHALES (EUBALAENA), USING DNA-FINGERPRINTING

The North Atlantic right whale (Eubalaena glacialis) is the most endan gered large whale in the world and shows few signs of recovery despite over 60 years of protection. In contrast, the South Atlantic right wh ale (E. australis), a closely related species, appears to be recoverin g successfully. Using DNA extracted from skin biopsy samples and two h ypervariable minisatellite probes, we compared the levels of genetic d iversity within the two populations. Our results revealed that unrelat ed North Atlantic (NA) right whales exhibit significantly less genetic variation than unrelated South Atlantic (SA) right whales (Jeffreys 3 3.15 (J33.15) probe: SNA-U-observed = 0.56 versus SSA-U-observed = 0.3 7, p < 0.01; M13 probe: SNA-U-observed = 0.74 versus SSA-U-observed = 0.46, P < 0.01). The level of band sharing among unrelated North Atlan tic right whales was greater than that predicted for second-degree-rel ated South Atlantic right whales (J33.15: SNA-U-observed = 0.56 versus SSA-2 degrees-expected = 0.53, p < 0.05; M13: SNA-U-observed = 0.74 v ersus SSA-2 degrees-expected = 0.60, p < 0.01), indicating that the no rthern animals have lost a substantial amount of genetic variability. Observed band sharing among North Atlantic first-degree relatives was lower than expected, based on band sharing among unrelated animals (J3 3.15: SNA-1 degrees-observed = 0.67 versus SNA-1 degrees-expected = 0. 78, p < 0.01; M13: SNA-1 degrees-observed = 0.83 versus SNA-1 degrees- expected = 0.87, p = 0.15). This suggests that the matings between clo sely related Individuals that would have resulted in the higher band-s haring values were unsuccessful. These results, in conjunction with be havioral and population data which indicate that North Atlantic right whales may be suffering from reduced fertility, fecundity, and juvenil e survivorship, support the hypothesis that inbreeding depression is i nfluencing the recovery of this species.